David Davis says case for secret courts based on a ‘falsehood’.

Former shadow home secretary says government’s argument ‘blown out of water’ following US leak about British double agent.

David Davis has said that the ‘American system leaks far more than the British ever could’.

Photograph: Martin Argles for the Guardian.

The government’s central argument for the creation of new generation of secret courts has been “blown out of the water” by the leak of highly sensitive British intelligence in the US, according to former shadow home secretary David Davis.

Ministers are stepping up plans to expand secret hearings into civil courts at the behest of MI5 and MI6, amid concerns that the US authorities will cut off the flow of intelligence if details emerge in open court.

But in a Guardian article, Davis calls on ministers to face down the demands after details were leaked in the US about a British double agent instructed by al-Qaida in the Arabian Peninsula to blow up an aeroplane with a highly sophisticated underpants bomb.

“This argument has been blown out of the water by last week’s disclosures, which demonstrate that the American system leaks far more than the British ever could,” Davis writes. “This leak happened not in the pursuit of justice but as a casually irresponsible piece of political spin.”

Ministers have been under fire from civil liberty groups over plans to allow some material to be concealed from the public, the media and claimants during civil trials. The proposals are a response to the public airing of evidence during litigation brought on behalf of Binyam Mohamed and other former detainees in Guantánamo Bay.

The deputy prime minister, Nick Clegg, raised concerns about the plans in a letter to ministers on the national security council. Clegg said the courts should only be used in exceptional cases where there are national security concerns.